The present invention relates to an apparatus for controlling the amount of delivery in a wrapping material feed system.
As a wrapping material feed system for cutting a wrapping material into a predetermined size and sending it to a wrapping machine, there has been known a system of a construction in which two bobbins each with a wrapping material wound thereon are provided and the wrapping material on one bobbin is drawn out by a delivery roller, then after being cut into a predetermined size, it is sent to a wrapping machine, while switching is made to the other bobbin side when the volume of the wrapping material remaining on one bobbin becomes small.
According to the above wrapping material feed system, a plurality of tension rollers are disposed between the bobbins and the delivery roller to cope with variations in the amount of delivery of the wrapping materials at the time of starting or stopping operation or at the time of change-over from one bobbin to the other.
Recently, with speed-up of wrapping operation, studies have been made about enlarging the winding diameter of wrapping material to reduce the frequency of replacement of wrapping material also in wrapping material feed systems.
The larger the winding diameter of wrapping material, the larger the variation in the amount of delivery of wrapping material at the time of starting or stopping operation or at the time of change-over of bobbins, thus requiring a larger number of tension rollers to be provided.
However, disposing a larger number of tension rollers causes the problem of a larger space required and troublesome maintenance. Moreover, with tension rollers, there is a limit and it becomes impossible to cope with the increase in the winding diameter of wrapping material.